1. Field of the Invention
This invention relates to a picture projecting device which is capable of projecting a clear picture in a bright environment.
2. Description of the Prior Art
When showing data to a number of people at a meeting, presentation, class and the like, devices such as video projectors, overhead projectors, or slides are used to enlarge the data and to project them onto a screen.
When doing so, the sunlight coming in from the window or the light from the room light reflected on the screen make it difficult to see the projected pictures, so there was a need to close the curtains of the windows and turn out the light to make the room dark.
However, the darkness of the room was inconvenient for the listeners who needed to read printed material or take a memo, and there was a device such as spotlight needed at their side.
So, in Japanese Laid-open Utility Model No. 3-5147, there is an idea mentioned where a polarizing board having the same polarizing trait as that of the output portion of the liquid crystal panel of a liquid crystal projector is used as the screen so that the influence of outer light would be reduced.
The idea taught in the Utility Model could only reduce the influence of outer light when a picture from a liquid crystal projector was projected to a transmitting screen.
But in an airplane where a video projector is used, all the blinds on the windows had to be shut as well as turning off the room light to cut off outer light when projecting a video, and passengers were troubled by having to shut the blind on the window by themselves. So, there was inconvenience in having to trouble even the passengers who did not want to see the video.
Therefore, the present invention offers a picture projecting device which projects a clear picture even in a bright environment by cutting out the influence of outer light, regardless of the kind of projector used.